feat(plugins): allow to import separate plugins

Created by: Johann-S

Finally I succeed to achieve that !

With that PR, folks will be able to choose which plugins they want to import and not all of our plugins.

Examples:

Importing Util

import $ from 'jquery';
import Util from 'bootstrap/js/dist/util';

Importing Popover

import $ from 'jquery';
import 'popper.js';
import 'bootstrap/js/dist/tooltip';
import 'bootstrap/js/dist/popover';

This PR would help a lot in that case: https://github.com/symfony/webpack-encore/issues/338

TODO

• Update our docs

Fixes: #26757 (closed)